AROMATISATION PROCESS

The invention concerns a procedure for the production of aromatic hydrocarbons according to the managing patent claim.

Task of the invention is it to make metal catalysts available whose activity is clearly increased compared with conventional catalysts and which permit the production of aromatic hydrocarbons under relatively moderated conditions in acceptable yields.

As catalyst 0,0t to 10Gew. % gallium are used according to invention or gallium connection containing catalysts. Preferred gallium connections is gallium oxide, gallium sulfate and gallium ions, which approximately in the superficial hydroxyl groups of surface-active oxides, as are exchanged hydratisiertem silicon dioxide or hydratisiertem alumina, contained hydrogen atom.

The gallium portion in these catalysts amounts to preferably 0.1 to 6 thread %, related to the entire carrier quantity in the catalyst. Special examples of carriers according to invention used of the catalysts with a content of gallium or gallium connections are aluminas, like AJuminiurnoxid, y-alumina and boehmite, Alumhueumoxide and Sfli-5 ciumdloxid, which if necessary hydroxyl groups at the surface contained, in which hydrogen atoms are exchanged by gallium -, aluminum -, iron and/or nickel ions, activated charcoal and fireproof gallium oxide, preferentially are Sfliciumdioxkitraeger, in particular sol before, with those an exchange the hydrogen of atoms described above was made the catalysts become manufactured, by endorsing the carrier with an aqueous solution of a soluble gallium connection, for example gallium nitrate, imprae ts the in this way formed paste under decreased pressure to dry ones evaporated and afterwards in an air flow at increased temperatures pyrolysiert if the use is desired vc.i surface-active silicon dioxide or Aluminiumoicid as carriers, can hydrogen atoms in the hydroxyl groups by gallium ions is exchanged.

According to invention used the catalysts know also different metals such as nickel, cobalt, iron, manganese, thallium, palladium, platinum, Indium, Garmani over, chrome, tin and/or zinc in small quantity containing, in order to improve the catalyst activity.

Nickel and nickel connections prefers the in such a way manufactured catalysts being able for example in form of a fixed bed are present,! and in the reaktionsrohr to be activated. The activation is made by rinses of the catalyst with a suitable gas such as nitrogen or air, at the intended reaction temperature.

As output products for the procedure according to invention can be used e.g. n and ISO butane or pentanes. These connections are led over the catalysts specified above and hydrogenated to Monoolefinen with the same coals s t OF fan number de. In addition the satisfied hydrocarbon becomes at a temperature from 400 to 750"C, preferably 500 to 600°C, under formation of the Monoolefins over the gallium catalyst geleite L for the dehydrogenation of satisfied hydrocarbons, which are because of the lowest end of the indicated range, is necessary higher temperatures, while with increasing number of carbon atoms smaller temperatures lead within the indicated range to optimal yields. The dehydrogenation is accomplished with a Reak tionsdruck from 1 to 20 bar, preferably 1 to 5 bar. The dehydrogenation takes place preferably in an atmosphere, as for example a hydrogen or a nitrogen inert on the reaction conditions. For it hydrogen, the waeh can be used the dehydrogenation in situ formed is rend. The received Monoolefine can be identified and isolated afterwards. Thus one receives propylene and Butene from butanes from Prapan. The insatiated hydrocarbons are then dimerisiert in such a way and so insatiated hydrocarbons with 6 to 16 carbon atoms are received. The dimerization is appropriately accomplished over the same catalyst as for the dehydrogenation, whereby one preferably preferably leads the Monoolefin at temperatures from 20 to 300"C 5G to 250° C with 1 to 130th 3 to 100 bar, over the catalyst. The conversion is accomplished appropriately in an atmosphere, like hydrogen or l nitrogen, iner'en on the reaction conditions, the products received with the dimerization, can be isolated and aromatized then or be used however without previous isolation directly for the production of the aromatic products.

Aromatizing preferably takes place at temperatures from 5,400 to 750*0. 500 to WC, whereby preferably in an inert atmosphere one works. The Aromatlsienmg is preferably accomplished with a pressure from 1 to 20 bar, 1 to 5 bar. Subsequently, the reaction products, mainly aro of 10 Malian hydrocarbons, are identified and isolated. In accordance with this procedure hydrocarbons with 8 carbon atoms can be converted to Xylolen.

In addition, the dehydrogenated product can be dimerisiert without previous isolation directly in a stage to olefinen with 6 to 15 16 colic attack material atoms and then aromatized. For example propane can be dehydiert to propylene, which can be dimerisiert and aromatized afterwards in a stage to benzene. In similar way tonn ISO butane to Isobuten dehydrogenates 20 and to be afterwards dimerisiert and to Xylolen aromatized.

The dehydrogenation, dimerization and aromatizing can run off at the same time. The per A can be controlled by careful control of the reaction conditions duktgemisch. Generally the dehydrogenation at the lower limit of the indicated temperature range runs off with given exit a Hiaterial, protecting the dimerization and Cycuesierung to the appropriate aromatic Koh x lenwasserstoff at the upper limit of the same temperature range main advantage of the erfimidngsgfcrjaessen procedure in it, daB the Deb.ydriereng is appropriate for prevail-prevailing that. Dimerization and aromatizing using in the same way Kataly 35 sators to be accomplished can. Thus a satisfied hydrocarbon with application of a combination of reaction conditions waiter only one catalyst can be converted to an aromatic Probdukt. Furthermore it is possible to convert a mixture 40 from satisfied and insatiated hydrocarbons in only one stage into the desired aromatic product. Thus a raw material with 4 carbon atoms, which contains butanes, Butene and/or butadiene, in only one Reaktionsge 45 can be converted faess without isolation from intermediate products to Xylolen.

Production of 6%igen Gai Oj/y alumina catalysts a solution of 10g gallium Nile advice SHjO) in approximately 30 ml distilled water is shifted with 26,6 g 7-Aluminiumoxid and mixed to a mash. The mash is evaporated over night under mining 55 dertem pressure to dry ones and afterwards 6 hours up in air on 550° C heats one receives on alumina applied gallium oxide (6 thread % gallium).

A solution of 4$ g gallium nitrate EO (Ga(NOj)b 8HjO) in 15ml distilled water with 13g in 15ml distilled water Crosfields U 40-Siliciumdioxid shifts the mixture over night under decreased pressure to dry ones evaporated and then 6 hours in air on 500° C heats up it one receives on silicon dioxide applied gallium oxide (6 thread % gallium).

Production of silicon dioxide catalysts 400 g Crosfields U 40-Si Iiaeumdioxid exchanged with gallium ions by 3taegiges being located in 1 litre distilled water hydrolyze the silicagel received after the Abdekantieren of the water 6 hours are left untouched under 4 litres of 2 n-nitric acid and washed then with 12 litres distilled water in a Bfichner funnel. The silicagel will finally 72 hours with 200°C dried and on that 72 hours with 500°C in air calciniert 4,5 g gallium nitrate (Ga(NO SHzO) to become in 200 ml distilled water 30 ml the managing received silicagel to become solved to a glass column given and 18 hours with the gallium nitrate solution perkoliert the catalyst will finally with 1500 ml distilled water washed and waiters night under decreased pressure dried before application the silicon dioxide catalyst exchanged with gallium (0.6 thread % gallium) 6 hours in air on 550°C heats up similar catalysts with a higher gallium portion (for example 13 thread % gallium) to become ago * placed, by making an exchange with further quantities of gallium nitrate on controlled pH conditions production of Ga2(VSiliciumdioxid-KatalysatorenEine solution water distilled by 4.9 g gallium nitrate (Ga(NO3)3 BHiO) in 15 ml with 13g in 15 ml distilled water suspended Crosfields U 40-Siliciumdioxid shifts the mixture over night under decreased pressure to dry ones evaporated and then 6 hours in air on 550° C heats up one receives on silicon dioxide applied gallium oxide (6 thread % gallium).

The example describes the invention. The retention time is computed on standard conditions (Oe°C, 1011 m bar).

Example ISO butane is led over a Galltumoxidauf silicon dioxide catalyst (6Gew. % gallium). The reaction temperature amounts to 590°C and the retention time 6.2 seconds. To 2,5minuetigem flowing through 65.1% of ISO butane one keeps converted as hauptprodukte (Ausbeaten in thread %) butanes (393%). Butene (38,7%), Ci-gs-Kohlenwasser of materials (9,4%) and aromatic hydrocarbons (9,2%). The xylene portion in the aromatic hydrocarbons amounts to 63 thread %. In the case of a feedback of the entire Gt-hydrocarbons a selectivity results regarding aromatic hydrocarbons of 42,4% and regarding Xylole of 293%. After tstuendigem flowing through the activity is unchanged